Downhole seal assembly having embedded sensors and method for use of same

Abstract

A downhole seal ( 50 ) includes an elastomeric element ( 98 ) operably to provide a seal between two downhole components. A strain sensor ( 102 ) is embedded in the elastomeric element ( 98 ). The strain sensor ( 102 ) has a mechanical flexibility that is substantially matched to the mechanical flexibility of the elastomeric element ( 98 ). The strain sensor ( 102 ) is operably connected to circuitry that is operable to identify changes in a property of the strain sensor ( 98 ) indicative of the strain being experienced by the strain sensor ( 98 ), which is representative of the strain experienced by the elastomeric element ( 98 ).

1. A downhole seal comprising:
 an elastomeric element operably to provide a seal between two downhole components; 
 a strain sensor embedded in the elastomeric element, the strain sensor having a mechanical flexibility that is substantially matched to the mechanical flexibility of the elastomeric element; and 
 circuitry operably connectable to the strain sensor, the circuitry operable to identify changes in a property of the strain sensor indicative of the strain being experienced by the strain sensor. 
 
   
   
     2. The downhole seal as recited in  claim 1  wherein the strain sensor further comprises alternating layers of an inorganic material and an organic material. 
   
   
     3. The downhole seal as recited in  claim 2  wherein the inorganic material is electrically conductive. 
   
   
     4. The downhole seal as recited in  claim 2  wherein the inorganic material is selected from the group consisting of metals and metal oxides. 
   
   
     5. The downhole seal as recited in  claim 2  wherein the organic material is selected from the group consisting of polymers and elastomers. 
   
   
     6. The downhole seal as recited in  claim 1  wherein the strain sensor further comprises multiple oppositely charged layers of at least a first and a second material held together by electrostatic charges. 
   
   
     7. The downhole seal as recited in  claim 1  wherein the strain sensor is embedded within an elastomeric element of a downhole seal assembly operable to provide a seal between a production tubing and a wellbore. 
   
   
     8. The downhole seal as recited in  claim 1  wherein the circuitry identifies changes in an electrical property of the strain sensor as an indication of the strain being experienced by the strain sensor. 
   
   
     9. The downhole seal as recited in  claim 1  wherein the circuitry identifies changes in a magnetic property of the strain sensor as an indication of the strain being experienced by the strain sensor. 
   
   
     10. A downhole seal assembly comprising:
 a tubular element; 
 first, second and third elastomeric seal elements disposed about the tubular element and operable to provide a seal between the tubular element and a wellbore when in a sealing position, the second seal element being disposed between the first and third seal elements; 
 a setting assembly disposed about the tubular element and in contact with the first and third elastomeric seal elements, the setting assembly operable to actuate the first, second and third elastomeric seal elements from a non-sealing position to the sealing position; 
 a strain sensor embedded in at least one of the first, second and third elastomeric elements, the strain sensor having a mechanical flexibility that is substantially matched to the mechanical flexibility of the elastomeric element in which the strain sensor is embedded; and 
 circuitry electrically connectable to the strain sensor, the circuitry operable to identify changes in an electrical property of the strain sensor indicative of the strain being experienced by the strain sensor. 
 
   
   
     11. The downhole seal assembly as recited in  claim 10  wherein the strain sensor further comprises alternating layers of a metal and an elastomeric material. 
   
   
     12. The downhole seal assembly as recited in  claim 10  wherein the strain sensor is embedded in at least one of the first and the third elastomeric elements to detect strain concentrations near a point of contact with the setting assembly. 
   
   
     13. The downhole seal assembly as recited in  claim 10  wherein the strain sensor is embedded in the second elastomeric element to detect extrusion of the second elastomeric element under at least one of the first and the third elastomeric elements. 
   
   
     14. A downhole seal comprising:
 an elastomeric element operably to provide a seal between two downhole components; 
 a strain sensor embedded in the elastomeric element, the strain sensor formed of a conductive elastomer having multiple oppositely charged conductive and nonconductive material layers held together by electrostatic charges, the strain sensor having a mechanical flexibility that is substantially matched to the mechanical flexibility of the elastomeric element; and 
 circuitry operably connectable to the strain sensor, the circuitry operable to identify changes in a property of the strain sensor indicative of the strain being experienced by the strain sensor 
 
   
   
     15. The downhole seal as recited in  claim 14  wherein the strain sensor further comprises alternating layers of an inorganic material and an organic material. 
   
   
     16. The downhole seal as recited in  claim 15  wherein the inorganic material is electrically conductive. 
   
   
     17. The downhole seal as recited in  claim 15  wherein the inorganic material is selected from the group consisting of metals and metal oxides. 
   
   
     18. The downhole seal as recited in  claim 14  wherein the strain sensor is embedded within an elastomeric element of a downhole seal assembly operable to provide a seal between a production tubing and a wellbore. 
   
   
     19. The downhole seal as recited in  claim 14  wherein the circuitry identifies changes in an electrical property of the strain sensor as an indication of the strain being experienced by the strain sensor. 
   
   
     20. The downhole seal as recited in  claim 14  wherein the circuitry identifies changes in a magnetic property of the strain sensor as an indication of the strain being experienced by the strain sensor.